1. Field of the Invention
This invention relates to a slide apparatus applied to linear sliding portions of machine tools, various kinds of assembled apparatuses and test apparatuses.
2. Description of the Prior Art
The mechatronic techniques have been developed remarkably in recent years, and there is a slide apparatus as a basic and multi-purpose apparatus which supports such techniques. A slide apparatus is a unitary combination of a feed screw apparatus and a linear guide apparatus, and has been used with the development of the electronic industries, by being incorporated in apparatuses in various technical fields, such as a machine tool, a semiconductor manufacturing apparatus, a transfer apparatus and an industrial robot. With the development of the techniques, the uses of a slide apparatus have been widened, and this apparatus requires a higher accuracy, a higher speed, easier assembling and higher versatility.
The slide apparatus is provided with a raceway groove-carrying track rail, a slider slidingly movable on the track rail, a screw shaft engaged with a threaded portion of the slider, support plates supporting both end portions of the screw shaft, and a driving motor fixed to either one of the support plates and adapted to rotate the screw shaft. This slide apparatus is controlled electrically and electronically and adapted to guide various kinds of machines and tools which are to be positioned along a straight line.
When such a slide apparatus as a whole is changed with another in accordance with its purpose and scale, the cost increases, and the changing operation becomes troublesome and requires a long period of time. Therefore, the development of a slide apparatus capable of changing the sizes and performance thereof freely, being obtained at a low cost and carrying out a replacement operation speedily is demanded so as to deal with problems which would be encountered when changes occur in the sizes and table supporting and transferring performance of the slide apparatus.
As shown in FIG. 17, a conventional XY positioning table apparatus has track rails 106 fixed on a bed 105, an X table 102 moving forward and backward on the track rails 106 via sliders 113, track rails 108 fixed on a support base 114 on the X table 102, a Y table moving forward and backward on the track rails 108 via sliders 107, a driving motor 104 for an X axis fixed to the bed 105, and a driving motor 103 for a Y axis fixed to the X table 102. The XY positioning table apparatus further has a ball screw shaft 112 supported rotatably on the support base 114, which is provided on the X table 102 driven by the Y axis driving motor 103, via bearings 111, and a ball screw shaft 109 supported rotatably on the bed 105, which is driven by the X axis driving motor 104, via bearings 110. The X table 102 is moved on the ball screw shaft 109 in accordance with the rotation thereof, and the Y table on the ball screw shaft 112 in accordance with the rotation thereof.
In the XY table apparatus, the bearing 110 for the ball screw shaft 109 which is on the motor-provided side is provided on the inner side of the track rails 106, and the bearing 110 on the non-motor-provided side on end surfaces of the track rails 106. Therefore, even when the changing of the length of the track rails 106 and the replacing of the ball screw shafts are done, it is necessary to form bolt holes for use in fixing the bearings 110 and carry out the bearing fixing operations.
The ball screw-united type linear guide apparatus disclosed in Japanese Utility Model Laid-Open No. 193637/1988 is a unitary combination of a ball screw and a linear guide apparatus, which is provided with a guide rail having a groove and ball rolling grooves in both of its inner surfaces, a nut fitted loosely and movable axially in the groove of the guide rail via rolling balls, a ball screw shaft engaged with the nut, support units supporting both end portions of the screw shaft, and a driving motor fixed to one of the support units and adapted to rotate the screw shaft. The groove has a function of an oil reservoir for a lubricating and cooling oil. The support units are fixed to end surfaces of the guide rail by bolts via seal members so as to prevent the leakage of the oil. A cover fixed to the nut encloses the groove of the guide rail.
The known table transfer apparatuses include a table transfer apparatus of a structure in which a table is supported movably by a guide and adapted to be transferred by a feed screw shaft. This table transfer apparatus is provided with a guide rail having a C-shaped cross section and upper and lower rolling element raceway surfaces in the inner side surfaces, a table supported movably on the guide rail so as to be held between the inner surfaces of the guide rail via rolling balls, and a feed screw shaft screwed to the table. This feed screw shaft is rotated by a motor, one end portion of the feed screw shaft being supported pivotably on a bearing portion provided on one end portion of the guide rail, the other end portion of the feed screw shaft being operatively connected to a motor, which is fixed to the other end portion of the guide rail, via a joint (refer to, for example, Japanese Patent Laid-Open No. 298446/1990 and Japanese Patent Publication No. 61587/1995).
In a conventional slide apparatus, support plates supporting both end portions of a screw shaft are fixed end surfaces of a guide rail, so that the working efficiency and positioning operations in the assembling and disassembling of the apparatus for the maintenance thereof become low and troublesome respectively. When the length of the guide rail is changed, bolt holes are formed in a cut end surface thereof by a tapping process. To carry out the tapping process, it is necessary to use a fixing jig for securing the guide rail to a support base.
The feed unit apparatus disclosed in Japanese Utility Model Publication No. 28444/1995 has a structure in which a feed screw apparatus and a linear guide apparatus are unitarily combined, the feed unit apparatus being provided with an upper side-opened cross-sectionally C-shaped elongated guide rail having mutually opposed axially extending ball rolling grooves in both of inner side surfaces thereof, a nut block having in both of outer side surfaces thereof ball rolling grooves opposed to those of the guide rail, a feed screw shaft engaged with the nut block, and support units fixed to the guide rail and supporting the feed screw shaft so that the feed screw shaft can be rotated freely and cannot be moved axially. The positioning of the support unit is done by fixing the same to the guide rail by engaging pins implanted in the support units with the ball rolling grooves of the guide rail. The specification of this feed unit apparatus discloses various types of fixing structures for fitting the motor-side support unit in the guide rail. However, since the fitting portion has to be formed during the manufacture of the support unit, the fitting position of the support unit cannot be changed.